The present invention pertains to packet data communications and more particularly to a method for multi-device registration in a session initiation protocol based packet data communications system.
In packet data networks, standard session initiation protocol (SIP) based registration allows a user to register many different contact addresses, but not many different user terminal devices. Typically a user will register with a particular contact address to allow the network to locate their current position and terminate call traffic to that position.
In a situation where a user may have several different contact addresses, for example a personal computer coupled to the network via a SIP interface and a mobile station (cell phone) coupled via a SIP interface to the network, there is a problem deciding which user terminal device should be used when making a call to such a user with multiple terminal devices. The originator's client will query the network to determine a current location of the user and will need to decide whether it is likely that the user is located at his or her personal computer or his or her mobile station, for example.
Currently, session initiation protocol within packet data networks allow the network to INVITE a particular user at all his or her contact locations simultaneously. Alternately, some SIP based systems allow the call to a multi terminal device user to proceed to the various devices in a sequential list stored within the network. Some prioritization may be included in such SIP systems to allow some selection. These approaches create excessive traffic within the network and often lead to wrong choices of terminal devices for the user.
Accordingly, what is needed is a method to improve selection of a device and corresponding contact address that is likely to reach the called user without requiring expending excessive network resources by inviting the user at all registered contact addresses.